Kim JY, et al: Anterior Anorectocolonic Tubular Duplication in Infant

Journal of Korean Association of Pediatric Surgeons 55

pISSN 2383-5036 eISSN 2383-5508J Korean Assoc Pediatr Surg Vol. 23, No. 2, December 2017https://doi.org/10.13029/jkaps.2017.23.2.55 Case Report

Anterior Anorectocolonic Tubular Duplication Presenting as Rectovestibular Fistula in an Infant

Ja-Yeon Kim*,†, Joong Kee Youn*, Soo-Hong Kim, Hyun-Young Kim, Sung-Eun Jung, Kwi-Won Park‡

Department of Pediatric Surgery, Seoul National University Children’s Hospital, Seoul, Korea

Anorectal duplications account for only 5% of gastrointestinal duplications, and cases with involvement of the anal canal are much rarer. Nearly all anorectal duplications are posterior to the rectum; duplications located anterior to the normal rectum are highly un-usual, and only a few cases have been reported. We report the case of an anterior anorectocolonic duplication presenting as a rec-tovaginal fistula in a 2-month-old infant. After diagnosis, the duplication was excised completely without further intestinal complications.

Keywords: Anal canal duplication, Rectal duplication, Colonic duplication, Duplication, Rectovaginal fistula

Received: April 7, 2017, Revised: May 24, 2017, Accepted: June 21, 2017

Correspondence: Hyun-Young Kim, Department of Pediatric Surgery, Seoul National University Children’s Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Korea.Tel: +82-2-2072-2478, Fax: +82-2-747-5130, E-mail: spkhy02@snu.ac.kr

*These authors contributed equally to this work as first authors.†Current affiliation: Gastric Cancer Branch, Research Institute & Hospital, National Cancer Center, Goyang, Korea‡Current affiliation: Department of Surgery, Chung-Ang University Hospital, Seoul, Korea

Copyright © 2017 Korean Association of Pediatric Surgeons. All right reserved.This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

INTRODUCTION

Gastrointestinal tract duplications are rare conditions,

comprising 0.1% to 0.3% of all congenital anomalies.

Duplications can occur throughout the gastrointestinal

tract, from the mouth to the anus [1,2]. Anorectal dupli-

cations account for only 5% of all duplications and are

primarily found in the retro-rectal space. Anterior ano-

rectal duplications are extremely rare [3]. Anterior ano-

rectal duplications are tubular duplications connected to

the colon and open like a distal fistula, but are located

anterior to the rectum and behind the bladder and vagina.

It is challenging to diagnose anterior anorectal duplica-

tion, both because of its rarity and because it can present

in different ways. Perirectal abscess, fistula-in-ano, re-

current fistulae due to Crohn’s disease, infected dermoid

cysts, sacrococcygeal teratomas, and anterior sacral me-

ningoceles must be considered part of the differential di-

agnosis [3,4]. Here, we present the case of an anterior

anorecto-sigmoid colonic tubular duplication initially

presenting as a rectovaginal fistula in a 2-month-old

infant. We also provide a brief literature review.

CASE REPORT

A 2-month-old female infant presented to our hospi-

tal with a 1-month history of stool passing through the

vagina. She was born at 36 weeks’ gestation weighing

1.875 kg and was the second infant of a twin. She had a

ventricular septal defect that closed spontaneously at 1

month of age. Initially, she was diagnosed with a rec-

tovaginal fistula. Despite conservative therapy, includ-

ing a sitz bath, for 5 months, there was no improvement

in her symptoms, and most of the stool still appeared to

pass through the vagina. A colon study indicated a rec-

tovaginal fistula directly connected to the distal rectum

(Fig. 1). Under general anesthesia, a small opening lo-

cated posterior to and near the vagina at vestibule was

found. The structure that had been misdiagnosed as a fis-

tula based on the colon study was not present. The patient

had a normally sited anus, an anterior ectopic anus, and

a double vagina (Fig. 2). A catheter was inserted through

J Korean Assoc Pediatr Surg 2017;23(2):55-58

56 Journal of Korean Association of Pediatric Surgeons

Fig. 1. A preoperative colon study appeared to show that the contrast

had passed to the vagina through a rectovaginal fistula (arrows).

Fig. 3. Intraoperative findings. (A) The

intraoperative contrast study revealed that the contrast injected via the an-

terior anorectal duplication filled the

normal colon and rectum and that there was a connection between the dupli-

cation and the normal colon at the level

of the proximal sigmoid colon. (B) Intraoperative sigmoidoscopy at the

merging point revealed that a catheter

inserted via the anterior anorectal duplication could be observed by a

scope inserted via the normal anus.

Fig. 2. Examination under general anesthesia revealed a normal anus,

an anterior anorectal duplication (catheter-inserted state), and dupli-

cate vaginal openings.

the ectopic anus, and an intraoperative contrast study and

sigmoidoscopy were performed. A parallel tubular du-

plication with a common wall was found. The common

wall extended 5 cm from the anal verge to the sigmoid

colon and then 20 cm to the level of the proximal sigmoid

colon. Proximally, the anterior duplication and normal

colon merged and formed a normal colon. Because most

of the stool moved through the anterior duplication and

because the diameter of the anterior duplication was

larger than that of the normally located colon (Fig. 3),

complete resection of both the anterior duplicated bowel

and posterior native bowel up to the merging point with

colo-anal anastomosis was performed (Fig. 4). Fig. 5

shows a schematic diagram of surgical findings. Pathologic

examination confirmed a duplicated colonic segment

with a common proper muscle layer. The patient was dis-

charged on the 8th postoperative day without incident.

During a 3-year follow-up, she defecated normally

without complications.

DISCUSSION

Gastrointestinal tract duplications occur with an in-

cidence of 1 in 4,000 to 5,000 live births. The incidence

of anorectal and colonic duplications has been reported

as 3% to 8% and 4% to 18% of all duplications, re-

Kim JY, et al: Anterior Anorectocolonic Tubular Duplication in Infant

Journal of Korean Association of Pediatric Surgeons 57

Fig. 4. Operative findings. (A) The tu-

bular anorectocolonic duplication and

the normal anorectum were dissected from neighboring structures. (B) Re-

sected specimen.

Fig. 5. Schematic diagram of surgical findings.

spectively [3,5,6]. Anorectal duplications comprise a

small proportion of enteric duplications, with only 70

cases reported to date in the literature. Based on their

embryogenesis, anorectal duplications would be ex-

pected to be located posterior to the rectum. In fact, most

anorectal duplications are located posterior to the anus;

anterior rectal duplications are very rare, with fewer

than 10 cases reported [7].

Although the causes of alimentary tract duplication

are uncertain, many theories have been proposed to ex-

plain their pathophysiology, including the abortive

twinning theory, persistent embryonic diverticular theo-

ry, split notochord theory, and aberrant luminal recanal-

ization theory. However, no single theory can explain all

forms of intestinal duplication [2,6,8]. Anorectal dupli-

cations are generally attributed to a simple “pinching off”

of the diverticulum in the 8th to 9th week of gestation or

to more complex “caudal twinning” occurring when the

embryo is 10 mm in length during the 5th week of ges-

tation [3].

Symptoms and findings depend on the location of the

duplication [2]. Most patients with anorectal duplica-

tions are asymptomatic. The most frequent symptoms in-

clude progressive constipation, prolapse of the anorectal

mucosa, and mucosal discharge. More severe symptoms

have also been reported, including recurrent fistulae,

pain, or infection in the duplicated cyst, rectal bleeding

from ulceration, or ectopic gastric mucosa. The severity

of these symptoms increases with the age at presentation.

Malignant degeneration of duplications has also been re-

ported [3,9,10]. The symptoms reported for anterior ano-

rectal duplications are similar to those for posterior ano-

rectal duplications, including recurrent gastroenteritis

and failure to thrive, isolated rectal bleeding, chronic

constipation with soiling, and rectal prolapse [7]. Due to

the differing presentations for anterior anorectal dupli-

cations, various diseases must be considered part of the

differential diagnosis, including sacrococcygeal ter-

atoma, anal fistula due to Crohn’s disease, rectal pro-

lapse, dermoid cysts, hydrocolpos, chordoma, leiomyo-

sarcoma, and hydrometrocolpos [3,4,7]. Because it is

challenging to distinguish anterior anorectal duplica-

tions from other diseases, delayed diagnosis can occur

[4].

J Korean Assoc Pediatr Surg 2017;23(2):55-58

58 Journal of Korean Association of Pediatric Surgeons

Duplications of the hindgut, such as anorectal dupli-

cations, are frequently accompanied by genitourinary

tract anomalies and have complicated structures; thus,

they tend to be challenging and complex. When encoun-

tering such duplications, genitourinary tract involve-

ment should be considered [2].

Various diagnostic modalities can assist in diagnosis,

such as abdominal ultrasonography, contrast studies,

computed tomography, and MRI [7]. In particular, MRI

can provide multiplanar views, allowing identification of

pelvic structures and ruling out other diagnoses [6,7]. To

evaluate communication between duplications and nor-

mal bowels, contrast studies can be helpful in accurately

delineating the anatomy of the duplicated rectum [6]. In

the present case, we performed a preoperative contrast

study, but we initially misinterpreted the contrast spill as

a fistula. We reached a final diagnosis intraoperatively

after re-performing the contrast study. The second con-

trast study clearly revealed the anterior anorectocolonic

tubular duplication.

Total surgical excision of all duplications is recom-

mended because of the potential for long-term compli-

cations. If an anorectal duplication is not treated, secre-

tions accumulate in the lumen of the duplication, leading

to infection with age [1]. Malignant changes in anorectal

duplications have also been reported in adult patients,

although not in pediatric populations [1,10]. When there

was no evidence of fistula formation between the dupli-

cation cyst and vagina, cyst unroofing and residual mu-

cosa ablation was applied [7]. In the other case of ante-

rior rectal duplication without rectovaginal fistula, sep-

tum division via surgical staplers was performed [3].

The location of the duplication determines the direc-

tion of approach. Perineal or posterior sagittal appro-

aches in the prone position have primarily been used in

cases of posterior rectal duplication and anal canal du-

plication [1], whereas abdominoperineal approaches

have been chosen for anterior rectal duplications [3,7].

One reported case of posterior anorectal duplication ex-

tending to the colon was initially treated with a posterior

sagittal approach, but as the dissection proceeded cepha-

lad, it became difficult to manage, and laparotomy was

also performed [6]. In our case, a perineal approach was

first attempted because the lesion was misdiagnosed as a

rectovaginal fistula; however, when the anterior ano-

rectosigmoid duplication was found, the operation pro-

ceeded using an abdominal approach.

In summary, for infants who present with stool dis-

charging from the vagina, anterior anorectal duplication

should be considered as a differential diagnosis, despite

its rarity. Because it is challenging to diagnose, careful

evaluation is required.

CONFLICTS OF INTEREST

No potential conflict of interest relevant to this article

was reported.  

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